Method and apparatus for locating the direction of a source



jan. 29, i924. SLQL G. NASH METHOD AND APPARATUS FOR LOCATING THEDTRECTON OF A SOURCE OF VIBRATION Filed Nov. l, 1918 ss .u ai f3. 1 a LI i l .50....3 c i s Paienied Jan; l29,y 1924.

' UNiTED STATE wenn GEORGE Hl NASH, OIEL H-IGHBURY, LONDON. ENGLAND,ASSIGNOR TO WESTERN ELEC- TRIO COMPANY, INCORPORATED, OE'NEW YORK. N.Y., A CORPORATION YORK.

OF NEW METHOD AND APPARATUS FOR I'LOCATINJG THE DIRECTION OF A SOURCE 0F.VIBRATION f Appiieation filed rnweiiiber'i,4 191s. serial No. 261,435.

To z/ whom ton-ay conce/'n Bc it known that I, Gnoiior, llowAiin NasiiI`a subject ot' the King of (ii-cat. Britain. re siding atHighbury,London,England7 have invented certain new and useful Improvements in a Wethoiland Apparatus for Loeating thel')irection of a Source ot Vibration, otwhich the following is a tull. clear.

instrumentalities for disabling` or otherwise dealing' with Such'crattmay be ctfectivclv directed vagainst it. i

In accordance with a feature otl the invention they direction otA asource lot' vibration is determined by s vnclironousl)y rotating a'pluralit)v ot vibration-responsive devices and comparing the ctfect otthe vibrations on such devices in yvarious positions. Also in accordancewith this't'eatiire ot' the invention, the vibration-responsive devicesare arranged to be rotated b v synchronous inotorsunder the control ot`an indicating member so arranged that for any given position ot" theapparatus the indicating member and the vibration-responsive deviceslwill bear a certain definite ,directional relation, whereby theindicating' nicnibcr` in indicating the positiono'l thevibratiiiiif-rcsponsive devices, will also indicate or point to thcdirection ot' the Source of vibration.

lin accordance with another vfeature oll the invention` which rendersthe method and apparatus particularly applicable to the detection ofenemy craft by an observer who is also located upon a moving vessel orvehicle, the vibration-responsive devices are arranged to be towedorotherwise,maintained` cludinlc electric conductors over which themovement of the vibratiori-responsive devices nia)Y be controlled by theobserver. ln detectingsubi'iiariiie vcssels. the vibrationresponsivedevices will ordinarilv be mounted within a float or biiov which mayv be.towed beneath the surface ot' the. "aten These andother lfeatures ofthe invention will more clearly appear from the annexed speciiation anddrawings in which Fig. l is a diagrammatic view, partl in section, otlapparatus constructed in accordance with an embodiment otl the inventiondesigned i'or submarinel use; Fig. 2 is a diagrammatic view showing therelation ot' the devices illustrated in Fig. l to a. ship carrying' theobserver; and Fig. l is a diagrammatic. view ot the electric circuitsutilized in controlling the device shown in Fie'. l. i

ln general, the device shown in Fig. l

takes the forni ot' an elongated float `or buoy `havinr; substantiallystream-line voutlines which is arranged to be towed through the waterand to be n'iaintained below the -surface of the water. Because ot itssimilarity in outline to the ordinary tish, this device is con'nnonlyreferred to by those utilizing it as a tislnv and Jor convenience willbeso referred to in this specification.

The fish consists of a substantialfl)v c vliii drical containerindicated as a whole at 1.k

which is formed b v supporting a piece o't' sheet metal upon a pair ol't'oi'iiiers 2. These formers ina v be made ot' wood or some light metal,and may bc of any desired shape`v preferabl)v either circular oi' oval.-The tormers-Qand thesheet nietal sheath supported thereon torni acliaiiiber within which .are supported two sound-responsive devices 3and l. ln the embodiment of the invention shown, a pair ot parallellongitudinal 4. Mounted upon the nieniher are upper bearings 7, T, andupon the member (i the lower bearings 8, 8 in which are mounted forrotation thesound-responsive devices 3 and 4. Shafts 9, which arefixed-ly secured to the sound-responsive devices 3 and 4, are connectedto the armatures of a pair-oit motors 10 and; 11, which aresupportedupon athird parallel member lll secured to the orniers Thesound-responsive devices maybe of any dwell-known type and preferablytake the 'Y rially affecting the diaphragm; Therefore,

the sound-responsive device 3 is shieldedlon one side 'from soundvibrations and is sensitive to sound vibrations received only on its`diaphragm side. The sound-responsive device 4 differs from thesound-responsive device 3 only in that the shield or casinpart 17 isreplaced hy another diaphragm, there being two opposilelypdisposeddiaphragms and 3l, so that this souud-responsive device Will respond tosound received from any direction, except in a direction parallel to thediaphragm; that is to say. when: the sound-responsive device l ispositioned with the edge of the diaphragme pointing` inI the directionof the 'source of sound, the diaphragms Will 'not be affected.

Secured to the formers 2 are substantially conical projections 12 and13` also of sheetmetal, which form, together with the formers 2, airchambers' indicated at 3? and 15. These air chambers serve to givebuoyancy to; the entire device. They are proportionel so that thechamber containing the soundresponsive devices may he filled with fluidand the whole device arranged to llcatat a,

given point beneath the surface. Mounted on the rear conical extensionare a series of guiding fins 34, which serve to prevent roi stion of the'Whole device when towed through the Water. Thetowing is accomplished hv means of a. cable which extends from the towing vessel through aweight 36, common-- ly called the pilot ish, to the main ish l. Thiscahlealso'contains an electrical cali-lo comprising a number ofelectrical conductors Which are shown diagrammatic-ally inl Fig. 3. Thepilot fish 3G may he made ot' lead or other suitable` material which isprovided `with a passage through which the cable passes, which passageis so formed as to provide for .a gradual bend,.,of the (zahle.V TheFund tion o'thepilotshis to maintain the main :fish a suitable distancebelow the surface` of the water by cou'nteracting'tho 'rowing pull.which would have a tendency to pull the main fish Vto the surface. Thedistance hetvveen the piiot fish and the main fish may he adjusted, asmay alsothe weight ot' the pilot fish, so as to maintain the llsh atagiven distance heloW the surface ol the Water. In order to substantiallyprevent'the transmission of vih fation from the towing vessel throughthe cable to the main fish, the cable vadjacent the pilot and main lishis surrounded by a spiralvspring Wire indicated at 19 and 20.

l'n constructing the main fish special precautions are'talren to preventinterference or reflection oi the sound waves intermediate the sourceand the sound-responsive devices. lhus the chamber containing thesound-responsive devices is lilled with sea Water to prevent soundrefraction in passig `from the .surface of the .fish to such devices.Also the various'4 necessary partitions, supports and other a paratusWithin the fish are covered with ru her 37 or other sound deadening orabsorbing material. The body of the fish is very elongated so that theconical ends therej of are located a comparatively great distance fromthe' sound-responsive devices, so that such ends will not act as shieldswhen the 'sound-responsive devices are directed toward the ends of thefish.

' The synchronous motors for rotatin trated digrammaticall in Fig. 3 andcomprise two groups of e ectromagnets 21 and 22 which operate upon thearmatures 23' and 24 respectively. The two sound-responsive devices arenormally set so that the plane of' their diaphragme are at right anglesto each other, and this relation is maintained at all' times, since thearmatures of the nchronous motors are connected to the soundresponsivedevices, so that the axis of the armature is parallel to the plane ofthe diaphragm of the sound-responsive device driven thereby. The motors10 and 11 are oontrolled by the controller 'i with which they areconnected by means ot the'electric cable extending between thepoint ofobservation and the fish. This controller is provided with a pluralityof stationary conta-cts a, 6, c, d, c, f, g, h, e', j, Z, m ,and fn, anda movable contact arm 26. Contacts a and ii are electrically connectedto each other and to the motor magnets c and cc.' Similarly, contacts Z)and i are connected to magnets c and Zi, contacts c and j to magnets cand ci', (i and ,7c to magnets nl and d contacts e. and Z to magnets eand c, contacts 'f' and m to magnets f' and f, g and n to magnets g andg. It will he apparenti that as a result oi these connections, since thearm 26 is connected to one .side of a source of energy such as thehatthe sound-responsive devices 3 and 4 are 1lluslll) lill

the armature will maken complete rotation when earliyxiia'grnfetfhasheenenergized twice7 'which:will-occur:'durinof ach complete rotationolI thelarm ZLVs ntli'cated in Fig; Il ol the..drnwiirgs` thear'niaturesgl and 24 are normali'y Aeightangles t'oeach other as arealso the som'id-responsive -elements 3 and `4 connectedithereto; Sincethe correspondingly followlt will ,beatssunicd that the tislr and pilot`tish are being towed behind a ship lor-the purpose lrit-locating; thepresence ot cnr-my submarines".- 'lnder these conditions the ca.- blc 35:will be approximately three hundred t'eet in 'length yand the `distancebetween' the piloty and .mafinlishwill be approximatelyl lilly teet.'l"h`e`main fish itself .is in the.v

neighborhood often or li fteen Ifeet longr and is appiox-iluately oneand a half leet in diameter. `l-nder the conditions assumed 4the main`tishuuil'l b'e subii'ierged a-considerable distan'cebelow Athe-sinhiceand aconsiderable :is distance. trom thetowing ship," sok that. ythesound-responsive( devices 3 and 4 will not'be materially a-tiected by'thedisturba'nce creati ed by theprolpeller otthe towing ship.

The olosem'er`v on the t'tnvincr `ship vbeinet desirous oi'Jdeteriu'ini'ngl whether there is a submarine vessel inthe vicinitywill place the telephone` receiuer 2S tohis ear and' will'throwtliieswitch'Q) th the, riiht position.

of battery 38 and with either the microphones 3 or 4*, depeni'ling' upontheposition of the switch 2h.' VVithfthe switch 29 'iil'the positionshown it 'willbe' observwl vthat' the microphone 3 andthe telephone isare placed in series with the .battery with each other andLing"whereas-the microphone l is also inertial to the battery` butthrough the re sistancelf).4 This.resistanceltl willvbc ad- Viusted toybe the equivalent ol' the resistance ol' the telephone rtazeiver.Similarly with the switch 29 thrown to the right, the micro-` Iphone lwill'be ctmnect'ed in series with the telephone 2S `and thel microphone3 in' series` with the resistance, .il-fl. 'lhe purposel of theresistance 2li/z is to insurethat the same amount oi current is'lowingthrough the .microphones regardless ot' whether they are cut in circuitwith the telephonereceiver. lt has heen. demonstrated that themicrophones operate at their highest point o1c sen-- Sith/ity when theyare heated to a certain degree, and consequently as shown in Fig. il,`current always maintained flowing rough the microphones regardless oftitl `sl'wcilicallyy Vdescriluul abovel lt will befnoted that theytelephone ref" ceiver isloperativelyassociated with a sourcel whether ornot they'are associated with the telephone receiver, which current`serves to vmaintain the microphonesheated and atI their maximum pointot'sensitivity.

Since the microphone -l is responsive to sound received on either sideowing to its double kliaphragm construction, it is the more sensitive ofthe two microphones and will be usually used for detecting the presyence of enemy submarines. Assuming therefore, that switch 29 listhro\vn.to the righh the observer will then listen.l 1f there is anenemy submarine in the vicinity, unless the submarine should be locatedina position so that the'edge of the microphone is point-v ing?rdirectly towards it, thc sound, due to the l operation ol"` themachinery ot'fthe subniarine, will lie-picked up by the microphone 4 andheard by the observer in thereceiver 2S.

lt is extremely unlikely that the microphone 44 will have its yedgeexactly in the line of propagation of sound, but in any case, the,observer can explore by slowly rotatingthe handle 2G and both themicrophones 3 and 4. n'lountedndjaeent the arm 2G is a switch', thecontacts of whiclrare located at 2T. This switch is so arranged thatwhile the arm 2G is in motion,' the contact 2T is closed, thus closing ashunt across lthe receiver and preve`n`tin; r the listener from beingconfused v by the clicking sounds which would'othel'-, wise be presentin the receiver. This switch Iis particularly useful in a later stageoll the ol'ierationand where its function will be.- more tullydescribed.

Also included in lthe shunt circuit which passes through the contacts .Tis a key 32 which is normally closed. When explorinbr it is advantageousthat theyreceiver 28 be 'operatively associated with'thel microphonedurimgr the rotation ot' the arm 2(3,and the key 32 provides means tordisabling the shunt which will normally-be closed aboutthe receiver` dueto the closure ol oinitaets 2T. s soon as the presence ol' a submarinein tho 'vicinity is' indicated by a. sound inthe receive'rH, tlu`observer proceeds to locato the direction olI the submarine as follows.lle will rotate the arm 2li, maintaining: key 2li depressed untila-point is reachedv where no ell'ect is audible in the receiver 2H. lhiswill indicate that an edge ot the microphone Ll'- is pointed directly tothe source ot sound so that its, diaphragfms are not affected.Obviously` this indicates the direction ol the line ol" propagation ofthe sound and does not indicate whether the arm 2U points drectlytowards the source. ol' sound or directly awaymlroni it, since obviouslythere areltwo positions `1H() `apart where the dia-y 26 through 180during which' movement of the arm the receiver will be shunted by thecircuit including the contacts 27 and will compare the e'ect in hisreceiver at that point. Inasmuch as this comparison is very quickly madeit can readily be determined in which of the two positions of the'arm 26the maximum eiiect is heard in the receiver. Since the microphone 3 issound shielded on onev side, the masimiun effect in the receiver will beobtained when the unshielded or sensitive side is facing towards thesource of sound. inasmuch as' the microphones 3 and 4 are movedsynchronously with the arm 26, it is obvious that when the arm 26 isadjusted rst togive the minimum or no result in the microphone l andthen to produce a maxiinumresult in the microphone 3, it will pointdirectly to the source of sound, or in other words, to the submarine.The Whole arrangement is therefore direct reading and the arm serves asa direct reading indicator.

It is obvious that the method of determinin the direction of the sourceof sound as,

we las the apparatus disclosed herein may take a variety ofA forms andmay be used for other purposes than the detection 'of under water craft.

lVhat is claimed is:

, V1. Acoustic apparatus comprising a contailler, a pluralit elementsinounter therein, means te maintain said vibration responsive elementsat right angles to each other and Ato synchronously rotate said elementswithin said container, and means for translating the reV spouse of seidelements into observableeffee-ts. f i

2. A pia-ratas for determining the direction o a source of vibrationscomprising 'a vibration-responsive element having a pair of paralleldiaphragrms responsive to \vibra tions in all :directions exceptvibrations propagated along lines parallel to the plane of the surfacesof said diaphragms` a sccoud vibration-responsive element having..lr adiaphragm responsive to vibration propagated from points facing' said'diaphragm,

means for synchronously rotating said ele- 1 ments, and means fortranslating` the re@ spouse lor" sind elements into observable ef- A.paratus for determining the direction o' a source of vibrationcomprising a container, a pair ot vibration responsive elements mountedin sitid container with their .responsive surfaces substantially atright plurality of vibratie of vibration responsive synchronouslyrotating said elements andY maintaining them at right, angles to'each,other, spouse ofsaid elements into observableef' fects. 5. Apparatus for-determiningI the direction ol" a source of vibrations comprising a `nresponsive elements mounte for rotation, electrical means to control therotation of said elements, means and means for translating the retotranslate the response of said element into observable effects, andmeans at a distant point to indicate the position of said elements.

6. Apparatus for determining the direction of -a source of subaqueousvibration comprising a submergible buoyant body, a vtowing` ship forsaid body, a towin cable having one end attached to said ship and theotherA end attached to said buoyant body, vibration responsive devicesrotatably mounted in said body, means to rotate said vibrationresponsive devices, means for translating the response of said devicesinto .observable effects, means located on said towing ship to indicatethe position of said devices, electrical conductors associated with saidcable for connecting said responsive devices to said translating means,and a mass secured to said cable intermediate the towing ship and thebuoyant bod to compensatefor the upward lill of .t eV towing ship ofsaid buoyant bod) T. Apparatus for determining the direction of a sourceo f vibration comprising a` pair of microphones` a source of currentassociated with said microphones, a telephone I receiver in circuit withsaid course of current andone of said microphones, a resistance incircuit with said vsource ofl current and the other of said microphones,and means for intel-changing said receiver and said resistance.

In witness whereof, I hereunto subscribe my name.

G. H. NASH,

